Document WO 2005/08 0081 discloses a rotary element for a printing press which is provided with an encoder. The encoder is capable of generating a first periodic signal during the rotation of the rotary element. The encoder is connected to an evaluation unit which comprises at least one synthesiser for generating a second periodic signal which has a resolution, frequency or phase ratio relative to the first signal.
With this rotary element, the encoder is a physical encoder which is constituted, for example, by an encoder plate and an encoder sensor. The encoder sensor generates the first periodic signal in accordance with the rotation of the encoder plate.
The disadvantage of this rotary element is that the speed variations of the element are propagated in the evaluation unit and influence the output signal generated by the evaluation unit in a negative manner.